title: Identification of the endostyle as a stem cell niche in a colonial chordate.
abstract: Stem cell populations exist in "niches" that hold them and regulate their fate decisions. Identification and characterization of these niches is essential for understanding stem cell maintenance and tissue regeneration. Here we report on the identification of a novel stem cell niche in Botryllus schlosseri, a colonial urochordate with high stem cell-mediated developmental activities. Using in vivo cell labeling, engraftment, confocal microscopy, and time-lapse imaging, we have identified cells with stemness capabilities in the anterior ventral region of the Botryllus' endostyle. These cells proliferate and migrate to regenerating organs in developing buds and buds of chimeric partners but do not contribute to the germ line. When cells are transplanted from the endostyle region, they contribute to tissue development and induce long-term chimerism in allogeneic tissues. In contrast, cells from other Botryllus' regions do not show comparable stemness capabilities. Cumulatively, these results define the Botryllus' endostyle region as an adult somatic stem cell niche.
authors.affiliation: Institute of Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA. ayeletv@stanford.edu
authors.forename: Ayelet
authors.initials: A
authors.lastname: Voskoboynik
authors.forename: Yoav
authors.initials: Y
authors.lastname: Soen
authors.forename: Yuval
authors.initials: Y
authors.lastname: Rinkevich
authors.forename: Amalia
authors.initials: A
authors.lastname: Rosner
authors.forename: Hiroo
authors.initials: H
authors.lastname: Ueno
authors.forename: Ram
authors.initials: R
authors.lastname: Reshef
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Ishizuka
authors.forename: Karla J
authors.initials: KJ
authors.lastname: Palmeri
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Moiseeva
authors.forename: Baruch
authors.initials: B
authors.lastname: Rinkevich
authors.forename: Irving L
authors.initials: IL
authors.lastname: Weissman
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement; D049109:Cell Proliferation; D046528:Chimerism; D005838:Genotype; D018613:Microscopy, Confocal; D009024:Morphogenesis; D009928:Organ Specificity; D055153:Stem Cell Niche / Q000502:physiology*; D033581:Stem Cell Transplantation; D023001:Transplantation Tolerance; D014561:Urochordata / Q000166:cytology / Q000254:growth & development*